Client: memory, log seq, log fragments parity, LAN, storage services
Stripe Group, stripe group for x, y, z, L, M, N
-subset server into stripe group
-parallel client activities
-increased availability
-efficient log cleaning
Cache coherence
-single writer, multiple reader
-fileblock unit of coherence
write- request
-receive token
-manager revokes
Log cleaning
log segment evolution, writes to file blocks
– may belong to different files
Unix File System
{filename, offset} -> i-node -> data blocks on disk
Client node action
filename -> mmap -> metadata manager
Manager node actions
filename -> File Dir -> i-number -> i-map -> i-node a dir -> stripe group map -> storage server -> index node of logseg id -> stripe group map -> storage servers -> data blocks form -> storage severs
LRVM
– persistent memory layer in support of system service
Riovista
– performance conscious design of persistent – memory
Quicksilver
– making recovery a first clacks citizen in os design
Persistence
– need of os subsystems
– make virtual memory persistent
– subsystem designers 4 is performant
– use persistent logs to record changes to VM
VM -> replace VM
